A passenger and a freight train start toward each other at the same time from two points 300 kilometres apart. If the rate of the passenger train exceeds the rate of the freight train by 15 km/h, and they meet after 4 hours, what must the rate of each be?

Soluzione

A p a sse n g er an d a f re i g h t t r ain s t a r t t o w a r d e a c h o t h er a t t h e s am e t im e f ro m tw o p o in t s 300 ki l o m e t res a p a r t . I f t h e r a t e o f t h e p a sse n g er t r ain e x cee d s t h e r a t e o f t h e f re i g h t t r ain b y 15 km / h, an d t h ey m ee t a f t er 4 h o u rs, w ha t m u s t t h e r a t e o f e a c h b e ?

passenger trai n^{'} s speed : 45

freight trai n^{'} s speed : 30

Fasi della soluzione

Translate the problem into an equation:

x \cdot 4 + (x - 15) \cdot 4 = 300

Risolvi per

x, x \cdot 4 + (x - 15) \cdot 4 = 300 : x = 45

Trova speed

passenger trai n^{'} s speed : 45

freight trai n^{'} s speed : 30